Bark Beetle Defense

University of Missouri researchers, Dr. Heidi Appel and Dr. Rex Cocroft are  looking very carefully at how plants respond to the sounds that are produced by insect predators such as caterpillars. "The vibrations don't directly caused the change in chemical defense. What they do is prime the plant so that when the plant experiences the vibrations from feeding in the absence of a caterpillar, and then we challenge the plants with caterpillars, then the plants that have received the feeding vibrations make many more chemical defenses than those that didn't. Is it conceivable that trees would be able to generate the same kind of defense? Is your question that trees also might have the ability to perceive feeding by bark beetles? That that would contribute to their defenses? Yes. That is one of the things that we are really interested in. We have looked at the response of one kind of plant to one kind of herbivore and while it is possible that that is the only plant that is able to perceive meaningful environmental vibrations, we doubt that very much. And so the next stage of our research is to look at potential responses to acoustic stimuli in other kinds of plants including woody plants. Woody plants transmit vibrations much better herbaceous or succulent plants. There is every likelihood, I think, that the vibrational channel as a source of information could be even more important for woody plants than it is for an herbaceous plant like the one we studied.